Dog and human brains have 'voice areas' in same places

The first study to compare brain scans of non-primates and humans has revealed
that both dogs and humans have dedicated brain areas for voices, and they react in similar ways
when processing emotional cues.

First author Dr. Attila Andics, of MTA-ELTE Comparative Ethology Research Group in Budapest,
and colleagues report their findings in the Cell Press journal Current Biology.

"Although parallel evolution cannot be excluded," write the researchers, the study suggests
specialized voice areas in the brain began developing over 100 million years ago, when humans
and dogs last shared an ancestor. This is much earlier than expected.

The findings also reveal new clues about mechanisms of brain and behavior that may explain
the unique connection that has existed between humans and dogs for tens of thousands of
years.

Dr. Andics says the social environment of dogs and humans is similar, and their results show
they may also use similar brain mechanisms to process social information, which may explain why
the two species make such successful companions.

To conduct their unique experiment, which involved taking the same functional magnetic
resonance imaging (fMRI) brain scans of both humans and dogs, the researchers trained 11 dogs to
lie still in the scanner.

Dr. Andics says they were interested in finding out, for example, "how do dogs process dog
sounds, and how similar it is to the way humans process human sounds."

Same areas in dog and human brains respond to vocal sounds

To conduct their experiment, the researchers trained 11 dogs to
lie still in the fMRI scanner. Image credit: Eniko Kubinyi

While in the scanner, the canine and human participants listened to nearly 200 different
vocal sounds of people and dogs, many with emotional connotations, such as whining, crying,
laughing and playful barking.

The fMRI images showed that the same areas in the brains of both dogs and humans respond to
vocal sounds.

And it came as no surprise to the researchers that the responses were strongest
when the participants listened to sounds of their own species.

Plus, when they played vocal sounds loaded with emotional cues, the researchers found
striking similarities in the brain responses of both humans and dogs, as they note:

For instance, when the participants heard "happy" sounds, in both
species, the same part of the brain lit up more than for "unhappy" sounds.

Dog and human brains respond differently to non-vocal sounds

When the participants heard "happy" sounds, the same part of the brain lit up more than for "unhappy" sounds. Image credit: Borbala Ferenczy

Dr. Andics says they were very struck by these similarities. However, there were also some
key differences.

For example, reaction to non-vocal sounds compared with vocal sounds differed greatly between
the species.

In dogs, 48% of their sound-sensitive brain regions responded more strongly to non-vocal sounds than vocal sounds, compared with only 3% of sound-sensitive brain regions in
humans.

The researchers say the study is a first step in helping understand how our four-legged
friends are so good at sensing our feelings.

Dr. Andics says their method offers a completely new approach to looking at dogs' brains and
how they work, so we can "begin to understand how our best friend is looking at us and
navigating in our social environment."

In August 2013, Medical News Today learned of another intriguing study looking at
dogs and humans, where researchers in Japan concluded that owners' yawns are contagious to
dogs, and the response is likely empathic, rather than a result of stress.

Should this be
confirmed, then the researchers say it is significant because it could become a powerful tool for
exploring the root of empathy in animal evolution.

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